Isolation and identification of N-mercapto-4-formylcarbostyril, an antibiotic produced by Pseudomonas fluorescens.

Abstract

Pseudomonas fluorescens strain G308 isolated from barley leaves produces a novel antibiotic substance that was purified by preparative TLC and HPLC and identified as N-mercapto-4-formylcarbostyril (Cbs) by LC/DAD, IR, LC-ES+/MS, LC-ES-/MS, GC-EI/MS, LC-HRES+/MS, mass isotope ratios anal., 1H NMR and 13C NMR anal. The purified new antibiotic compd. is effective against many phytopathogenic fungi in vitro. The compd. inhibited at 25 ppm spore germination and germ tube growth of the following fungi; Fusarium oxysporum f. sp. lycopersici, Fusarium culmorum, Cladosporium cucumerinum and Colletotrichum lagenarium. At concns. up to 125 ppm, the compd. did not interfere with release of zoospores from sporangia and germination of encysted zoospores of Phytophthora infestans.

Isolation from Cussonia barteri of 1'-O-chlorogenoylchlorogenic acid and 1'-O-chlorogenoylneochlorogenic acid, a new type of quinic acid esters.

Abstract

1'-O-Chlorogenoylchlorogenic acid and 1'-O-chlorogenoylneochlorogenic acid, a new type of quinic acid esters, have been isolated, in addn. to six known quinic acid esters, rutin, and a mixt. of saponins, from the methanol ext. of Cussonia barteri Seemann (Araliaceae) leaves collected in Cameroon. Structure detn. was achieved by NMR, mass, IR, and UV spectroscopy. All compds. were tested for inhibitory activity on 5-lipoxygenase and cyclooxygenase-1, for antimicrobial activity against Bacillus subtilis, Pseudomonas fluorescens, and Cladosporium cucumerinum, and for haemolytic activity.

New entry to the synthesis of clerodane diterpenes. The first enantioselective syntheses of 7-oxo-kolavenic acid and methyl solidagonate.

Abstract

Using (1S,5S)-(-)-verbenone (I), readily obtainable from (+)-nopinone, as the chiral source, we have established the general method for prepn. of three kinds of key intermediates, conjugate enones II and III (R=?-H) for the syntheses of neo-trans-clerodanes and III (R=?-H) for those of neo-cis-clerodanes. Starting with the compd. III (R=?-H), the first enantioselective syntheses of (-)-(5R,8S,9S,10R)-7-oxo-cleroda-3,13E-dien-15-oic acid (7-oxo-kolavenic acid) (IV) and solidagonic acid (V) as its Me ester were achieved.

Diterpenoid and limonoids from the stem of Pterorhachis zenkeri

Abstract

One new diterpenoid, Me 3?-hydroxy-7-oxo-dehydroabietate (1), two new limonoids, 3?-deacetyl-amoorastatin (2) and 9?-amoorastatin (3), and the known limonoid amoorastatin (4) were isolated from the stem of Pterorhachis zenkeri.

Vanillic acid 4-O-?-D-(6'-O-galloyl) glucopyranoside and other constituents from the bark of Terminalia macroptera Guill. et Perr.

Abstract

A new phenolic glucoside gallate, vanillic acid 4-O-?-D-(6'-O-galloyl) glucopyranoside (I) was isolated from the bark of Terminalia macroptera Guill.et Perr., together with 3,3',4'-tri-O-methylellagic acid and two triterpene glucopyranosyl esters, 24-deoxy-sericoside and chebuloside II. Compds. 2-4, not described previously for this plant, showed antimicrobial activities against Bacillus subtilis, while 3 and 4 possessed hemolytic properties. In both assays 1 was found to be inactive.

Sesquiterpene lactones and a myoinositol from glandular trichomes of Viguiera quinqueremis (Heliantheae; Asteraceae).

Spring, O.; Zipper, R.; Reeb, S.; Vogler, B.; Da Costa, F. B.

Phytochemistry (2001), 57(2), 267-272.

Abstract

The ext. of the floral parts of Viguiera quinqueremis afforded, in addn. to known compds., six new sesquiterpene lactones (e.g. I) as well as a new myoinositol deriv. (II). All compds. were detected in glandular trichomes which were collected micromechanically from the anther appendages and were analyzed by HPLC. Structure identification was performed by 1H NMR measurements including LC NMR and LC MS expts.

Isolation and frontier molecular orbital investigation of bioactive quinone-methide triterpenoids from the bark of Salacia petenensis.

Abstract

The crude dichloromethane bark ext. of Salacia petenensis (Hippocrateaceae) from Monteverde, Costa Rica, shows antibacterial and cytotoxic activity. Bioactivity-directed sepn. led to the isolation of tingenone and netzahualcoyonol as the biol. active materials. Also isolated from the ext. were 3-methoxyfriedel-2-en-1-one (a new natural product) and 29-hydroxyfriedelan-3-one. The structures of these compds. were elucidated on the basis of NMR spectral anal. MO calcns. have been carried out using the semi-empirical PM3 and Hartee-Fock 3-21G ab initio techniques on the quinone-methide nortriterpenoids tingenone and netzahualcoyonol, as well as on the nucleotide bases adenine, guanine, cytosine, and thymine. The MO calcns. suggest that a possible mode of cytotoxic action of quinone-methide triterpenoids involves quasi-intercalative interaction of the compds. with DNA followed by nucleophilic addn. of the DNA base to carbon-6 of the triterpenoid.

Abstract

Two new hydrolyzable tannins, isoterchebulin (I) and 4,6-O-isoterchebuloyl-D-glucose (II), together with six known tannins, (III-VIII), were isolated from the bark of Terminalia macroptera. Their structures were elucidated by extensive 1D and 2D NMR studies, MS, and chem. transformations. Biol. activities of all compds. were evaluated against the snail Biomphalaria glabrata, the bacteria Bacillus subtilis and Pseudomonas fluorescens, the nematode Caenorhabditis elegans, and four cancer cell lines (Hep G2, MCF-7/S, MDA-MB-231, and 5637 cells). All compds. except III showed antimicrobial activities against B. subtilis (MIC 8-64 ?g/mL), whereas only I was active against C. elegans (100 ?g/mL) and B. glabrata (LC100=60 ?g/mL). III and VIII were toxic against 5637 cells with LC50=84.66 and 41.40 ?M, resp.

Application of LC-NMR measurements in phytochemical studies.

Vogler, B.; Spring, O.

Recent Research Developments in Phytochemistry (2000), 4 207-222.

Abstract

The application of LC-NMR investigations to plant exts. is shown. First a short introduction to the background of LC-NMR is given. Then phytochem. investigations using LC-NMR are discussed. Aspects like the screening of structurally closely related series of compds., phytochem. studies with limited access to plant material, and studies of unstable compds. are covered.